Telephone circuits



May 27, 1924. 3,495,295

H.V FLETCHER TELEPHONE CIRCUITS Filed April I:l, 1920 b y Afijn -when conversation is taking place.

acarrea parte HARVEY FLETCHER, OF NEW YORK, N. Y., ASSIGNOR A'.IO WESTERN' ELECTRIC CO- PANY, INCORPORATED, 0F NEW YORK, Y., A CORPORATION OF NEW YORK.

TELEPHONE CIRCUITS.

Application led April 1,

To all whom t may concern:

Be it known that I, HARVEY FLETCHER, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Telephone Circuits, of which-the following is a full, clear, concise, and exact description.

This invention relates to telephone circuits and apparatus, and more particularly circuits having provision for signaling.

It is well-known that a receiver and transmitter, if properly related to a source of current and if placed adjacent to each other may be made to howl or produce a sustained note.

. It is an object of this invention to utilize the above characteristic of the ordinary telephone instruments for calling',l thereb avoiding the necessity of using a calling bel or other auxiliary calling device.

A further object'of the invention is to enable the use of howling for signaling by relatively slight alterations of the ordinary telephone circuits and by the use of the ordinary source of current employed to energize the transmitter for talking.

. To accomplish these objects,'means is provided to place the receiver and transmitter of a substation set in mutually reactive relation when not in use for talking, so that an operator merely by plugging in a line connection to the -subscribers line or link circuit may close a circuit through the instruments and the central or other source of current and cause the production of the signal. Means is provided to cancel the signal when the subscriber lifts the receiver and to prevent reestablishing the signal when the receiver is replaced.

It is often desirable, and particularly so when a hand set is employed, that the substation be anti-side-tone during the period If the receiver were wholly anti-side-tone, however, even though it be placed adjacent the'transmitter, the set could not be made to howl.

-This :invention provides an arrangement for making the set side-tone when in position for si aling and making it anti-side-tone when 1n position l for conversation.

These and other obfects of the invention will be more fully un erstood from the following detailed'descriptio'n and claims taken in conjunction with the accompanying draw- 1920. 'serial 110.370,620.

ing, in which is represented diagrammatically a subscribers substation andlink circuit together with a line circuit to be connected thereto.

Referring to the drawing there is employed at the substation a hand set 1 comprising a transmitter 2 and a receiver 3. When handset 1 is not in use it is placed on a vertically moving stand or similar device 4 having a tubular member 4', the opposite ends of which` receive respectively the transmitter and the receiver. This provides a means for causing sound waves produced by the receiver to actuate the transmitter when it is desired to cause the set to howl.

A line wire 5 of the subscribers link circuit is connected `to one end of the receiver winding, and when the stand 4 is depressed, asshown in the drawing, line wire 5 is connected through part of the receiver winding and the transmitter to` ground at 6. When stand 4 is raised, contacts 11 are closed, and the link circuit 5, '9, is closed at the subscribers end of the circuit. The other end of the circuit is shown connected to a jack 8 at a central station, the line wires terminating in contacts 7' and 10, the function of which will be described later on.I

The operators cord circuit includes the source of Icurrent 13, grounded at 14, repeating coil 15,l ring-conductor 16, relay armature 50, contact 41, conductor 45 and ring contact 19 of the plug 8, with a return path by way of tip contact 36 of plu 24, conductor 21, relay 22, repeating coi 23, back to battery 13. The relay coils 18 and 22 have different' resistance values assigned to them and the relays function to select the the subscribers substation. This circuit in-L cludes the grounded battery 13, conductor 16, relay armature 50, contact 41, conductor 45, ring contactk 19 of the plug ring contact 7 of the jack, subscribers line wire 5, receiver 3, transmitter 2, contacts 11, and ground at 6. A 'secondaryfcircuit is simultaneously established through conductor 25, supervisory lamp 2o which a resistu ance to prevent the actuation of relay arma ture 5G, relay i8, conductor 27, resistance 28, sleeve if? of the plug 24, sleeve contact 29, conductor 30', and cut-ofi relay 31 to ground 32, to prevent the energisation of subscribers line lamp 33 by the oper tion o line relay from battery 35, in the usual manner.

lhe howling action produced by the current owing through the relatively adjacent transmitter 2 and receiver 3 can be terminated by the subscribers lifting the handset from the stand 4 and thereby preventing the reaction oi the receiver on the transmitter through member 4. As an additional precaution against howling when the handset is removed from the stand, the substation circuit is made anti-side-tone when contacts 11 are closed. 'lhe circuit employed is that disclosed in the application or' l?. W. Mclown, Serial No. 311,543, iled July 17, 1919. 'lhe transmitter is connected to an intermediate point on the receiver winding and fluctuating currents produced in the transmitter divide between the parts of this winding, one part going through the line and the other part going through a balancing impedance 60. The relative values of impedances and windings are such that no flux is produced in the receiver core when the transmitter is actuated. When the handset is on the stand, however, the circuit branch containing impedance 60 is open circuited and a circulation of energy between the transmitter and receiver is possible.

When the talking circuit is established by lifting the handset from its stand, supervisory relay 22 is energized and closes a shunt circuit at the contact 46 and armature 37 which shunts out the supervisory lamp 26. The resistance is sufiiciently less than that possessed by the lamp 26 to energize the relay 18 and withdraw the relay armature 50 from engagement with contact 41 thus interrupting the shunt circuit through that oint. A substitute circuit has, however. een established through conductor 42, armature 43 of relay 22 and conductor 44 so that the continuity of the talking circuit now established through the subscribers instruments is uninterrupted.

Upon completing his conversation and replacmg the andset, the subscriber breaks the circuit throu h the supervisory relay 22 at contact 11 and thereby releases the relay armatures 37 and Y43. lt will be seen that the release of the armature 43 breaks the shunt circuit at that point and as the relay coil 18 'is so wound that the current flowing therethrough is sufficient to hold the armature when already attracted, although not suilicient to move the armature from the released position, the current must now ilow action.. lo .li n Olii.'

x rater nas the enact ll circuits vreleasing the l l' breaking ture 5@ of relay lf3 restore all p 1 their normal condition shown in the draw ing..

l/Vhile one substation arrangement form of corel circuit adapted to be used m carrying out the invention have been shown and described, it is to be understood that the invention is not limited to the details of the arrangements disclosed, but is capable of employing a wide variety of apparatus embraced in the scope oi the appended claims.

What is claimed is:

1. lhe method oit operating a telephone substation, which comprises rendering said substation side-tone at times, causing said substation to howl at certain ot said times as a signal to the subscriber, and rendering said sub/station anti-side-tone for ending said signal.

2. 'lhe method of operating a telephone substation having a two winding receiver, which comprises sending current through only one of said windings when calling and sending current through both ont said windings when talking.

3. lin combination, a substation circuit comprising a branch having impedance to balance out side-tone, means operative to open said branch to render said circuit sidetone, and means acting through said sidetone arran ement to produce a sustained tone for ca ing. 1

4. lin combination, a line, a substation circuit comprising a receiver and a transmitter, means for lacing said instruments in circuit with bot sides ofsaid line for talking, and means for placing said instruments in circuit with one side oit said line and round :for calling. Y

5. n combination, a line, a substation circuit comprising a receiver and transmitter, means for placing said instruments in circuit with both sides of said line for talking, means for placing said instruments in circuit with one side or said line and ground for calling, and means associated with said ground circuit to produce howlingl of said instruments.

6. lin combination, a tele hone 'hand set, means causing interaction etween the receiver and transmitter to produce a sustained tone for signaling purposes, and means for preventing said interaction during conversation.

7. lin combination, a telephone hand set and a stand therefor, said? stand comprising means causing interaction between the reliti@ ill@ BCO

ceiver and transmitter to produce a sustained tone. v

8. In combination, a telephone hand set, a stand therefor comprising means causing interaction between the receiver and transmitter to produce a sustained tone, and means to prevent said interaction when said hand set yis removed from said stand.

9. In combination, a telephone substation comprising a telephone receiver and transmitter, a tubular support having seats for removably holding said instruments with their normally external faces directed toward the interior of said support, the interior of said support serving as a medium for the passage of sound waves from said receiver to said transmitter.

10. In combination, a telephone hand set comprising a receiver and transmitter, a tubular support for said hand set, the interior of said support serving1 as a medium forthe passage of sound waves from said receiver to said transmitter.

11. In combination, a telephone substation comprising a telephone receiver and transmitter for signaling in opposite directions respectively, means for energizing said receiver and said transmitter and means forming a confined passage for sound waves between the normally external faces of said receiver and said transmitter.

12. In combination, a telephone substation comprising a telephone receiver and transmitter for signaling in opposite directions respectively, means for energizing said receiver and transmitter, and a tubular member forming a passage for sound waves between the normally external faces of said receiver and said transmitter.

13. In a telephone system a line circuit, a transmitter and receiver associated therewith, a link circuit for connection with said line circuit, and means responsive to the connection of the link circuit with the line circuit to cause the transmitter and receiver to react upon each otherto produce an audible signal.

14. In a telephone system, a line circuit, a transmitter and receiver associated therewith, a link circuit for connection with said line circuit, means responsive to the connection of the link circuit with the line circuit to cause the transmitter and receiver to react upon eachother to produce an audible signal, and means for canceling said signal by lifting said receiver.

15. In a telephone system, a line circuit, a transmitter and receiver associated therewith, a link circuit for connection with said line circuit, means responsive to the connection of the link circuit with the` line circuit to cause the transmitter and receiver to rea'ct upon each other to produce an audible signal, and means for canceling said signal by lifting said receiver, and means to prevent the reestablishing of said signal when the receiver is replaced.

16. In a telephone system, a subscribers station having the transmitter and the receiver mounted in relatively adjacent relation, means whereby the operator may establish a circuit including said station and over which current may be sent having characteristics such that a howl is produced by said relatively adjacently placed receiver and transmitter, means for canceling said howl by lifting the receiver, and means arranged to control said circuit through saidl mitter, means for canceling said howl byy lifting the receiver, means arranged to control said circuit through said receiver and transmitter and prevent the rei-establishing of the howl when the receiver is replaced, and means for restoring the circuit to its normal condition when the switchboard connection is broken.

18. In a telephone system, a subscribers station having the transmitter and the receiver placed in relatively adjacent relation, means whereby the operator may make a plug connection to establish a branched circuit one branch of whichJ includes a current source and said transmitter and receiver and the other branch of which is a supervisory circuit including said current source, said circuit branch including said receiver and said transmitter having a resistance value such that a howl is produced by said receiver and transmitter, means whereby a branch current path so arranged as to cancel the signal and permit the transmission of speech is established by lifting the receiver, means in said supervisory circuit having controlling relation to said circuit including said receiver and transmitter, means in said branch current path arranged to place said controlling means in said supervisory circuit in condition to prevent the re-establishing of the howl when the receiver is replaced, and means for restoring said controlling means and said signaling circuit to normal when the plug connection is disrupted.

19. In a telephone system, including'- a transmitter and a receiver mounted in signaling producing relation, a supervisory circuit, a signaling circuit and a talking circuit havin a common current source, means where y the supervisory circuit and the signaling circuit are establishedv by a svvitchn board connection made by the operator, means whereby the lifting of the receiver establishes a talking circuit and cancels the signal, and means in the supervisory circuit and controlled by the talking circuit for acting on the signaling circuit and preventing the reestablishing of the signal When the receiver is replaced, said supervisory and signaling circuits being restored to normal when the switchboard connection is dise rupted. i

20- ln a telephone system including ai transmitter and a receiver mounted in adjanceaeea lifted, a resistance, and means in said branch for causing the diverting ot' vcurrent through L transmitter and a receiver mounted in signaling relation, a circuit arranged to be established by the operator to include a source of current and said receiver and transmitter, said circuit having a resistance value arranged. to produce a signal by said receiver and transmitter, means for diverting the current path to silence the slgnal and escent relation, a circuit arranged to be estab\c`tablish a talking circuit when the receiver lished by a central operator including a source of current and said receiver and transmitter, said circuit having a resistance value such that a signal Will be produced by the juxtaposition of said receiver and trans- `mitter, a circuit branch adjusted to silence said signal, means for diverting current through said branch when the receiver 1s is lifted, and means for including sucient resistance in the circuit to cause the signai to remain silenced until vthe operator has broken the circuit.

ln Witness whereof, li hereunto subscribe my name this 30th day of March A. D., i929 HARVEY rriicronnia. 

